Machine tool



Jan. 19, 1943.

Filed Aug. 3, 1940 M. I. MATHEWSON MACHINE TOOL 3 SheetsSheet 2' Patented Jan. 19, 1943 UNITED STATES PATENT OFFICE) MACHINE TOOL Maxwell I. Mathe wson; Providence, R. I., assigner to Brown and Sharpe Manufacturing Company, a corporation of Rhode Island Application August 3, 1940, Serial No. 350,359

11 Claims.

The present invention relates to improvements in machine tools, and is concerned more particularly with the organization of a rotary work supporting assembly particularly adapted for use in a grinding machine which includes specifically a work table, and a headstock and footstock mounted thereon.

It is one object of the invention to provide a work supporting assembly including a work table, a headstock and a footstock adapted for use in a grinding machine, of which the headstock and footstock are constructed and arranged to be readily interchangeable on the table so that the headstock may be located at one side or the other of the grinding wheel in accordance With the requirements of the particuiar work, as for example in shoulder grinding, to avoid interference of the headstock with the grinding wheel carriage and associated parts. v

Other objects of the invention relate more specifically to the improvement of the several associated devices comprising a work supporting assembly of this general description.

With these and other object in view as may hereinafter appear, a feature of the invention consists in the provision of a worksupporting assembiy including a work table with a headstock and a footstock supported -thereon, each of the headstock and footstock being mounted on swivel mountings on the table ways, and having their centering spindles respectively passing through the axis of the swive1 mounting so that the headstock and footstock may be readily interchanged to permit reversal in the position of the work on the table.

Another feature of the invention consists in the provision in a work supporting assembly of this generai description including a headstock having a headstock motor mounted integraliy therewith; of driving connections for the headstock motor which include a flexible cable and plug attachable at either end of the table to directionai motor driving electrical outlets Whereby the direction of rotation of the motor is automatically determined in accordance with the position of the headstock at the left or right hand end of the table through the attachment of the flexible cable and piug into the corresponding electrical outlet. Another feature of the invention consists in the provision in a grinding machine having a work supporting assembiy of this genera1 description including an interchangeable headstock and footstock, of a footstock spindle operating lever, and supporting means for the lever on which the lever is shiitable from one operating position to another to cause the lever always to be located on theside of the footstock facing the operator, regardiess of the direction in which the footstock faces at the left or the right hand end 'of the work table.

Another feature of the invention consists more specifically in the construction and arrangement of the footstotak including a centering spindle adapted for supporting footstock type diamond tool holders constructed and arranged to be mounted in two alternative positions enabling a single diamond tool holder to be employed and to be set at the correct operating angle for alternative positions of the footstock at either the left or right hand end of the table.

The severa1 features of the invention consist also in the devices, combinations and arrangement of parts hereinafter described andclaimed, which together With the adavntages to be obtained thereby will be readily understood by one skiiled in the art from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a view in rear elevation of a grinding machine, on1y so much of the machine being disclosed as is believed necessary to illustrate the connection of the present invention therewith; Fig. 2 is a view in rear elevation similar to Fig. 1, but with the headstock and footstock in their reversed positions; Fig. 3 is a view in right side elevation of the machine, that is, looking from the left of Fig. 2; Fig. 4 is a wiring diagram showing particularly the electrical connections including the receptacies at the right and left side of the machine for controlling the direction of the headstock muter in its alternative operating positions; Fig. 5 is an end view of the footstock looking from the left 01: Fig. 6; Fig. 6

is a view in front elevation of the centering spindle as shown in Fig. 5, with a portion of the frame broken away to show the underlying parts; Fig. 7 is a detai1 sectiona1 view taken on the line 1-! cf Fig. 6; Fig. 8 is a sectional view taken on the line 88 of Fig. 6; and Fig. 9 is a detai1 sectionai view taken on the line 99 of Fig. 6. I The grinding machine disclosed in the drawings as embodying in a preferred form the saveral features of the invention, comprises a base support Il], a table support 12 mounted to slide on ways M on the base H), and a grinding wheel spindle 'carriage l6 slidabiy supported in ways in a swive1 mounting [8 on the base la. As generafly indicated in Fig. 3 of the drawings, a grinding wheel 20 is supported at one end of a grinding wheel spindle 22, the other end of which carries a pulley 24 driven by means of a belt 26 and puliey 28 on the armature shaft of an electric motor 36.

The work supporting assembly of the machine comprises with the table support 14, a headstock 32 and a footstock 34 which With the present construction are carried respectively on swivel mountings 36 and 38 adjustably supported on a swivel table 40 on the table 12. As best shown in Fig. 3 of the drawings, the headstock 32 is provided with a center 42 and a work driving plate which is driven by means of a belt and pulley drive generally designated in dotted lines in Fig. from an electric motor 44 mounted in the headstock. The table 46 comprises a pair of positioning surfaces 46 and 48 which lie respectively in a horizontal and a vertical plane, and are constructed with a high degree of precision to insure the accurate location of headstock and footstock on the work table. Correspondingly shaped surfaces of the swivel support 36 are held firmly in engagement with the table by means of clamping screws 56 which extend downwardly at an angle through the swivel mounting 36, and at their lower ends are provided with enlarged heads which engage within a T-ghaped slot 52 in the table 40. The center 42 is arranged to extend through the axis of rotation of the headstock on its swivel mounting, so that the headstock will always be located in the identical position transversely of the table independently of whether the headstock is located at one end of the table facing 1eft as shown in Fig. 1, or at the other end of the table facing right as shown in Fig. 2.

In accordance with the usual practice in machines of this type, the grinding wheel 26 rotates in a direction which will cause the peripheral abrading surface to move downwardly againstthe work. The headstock is arranged to rotate the work in an opposite direction in which the engaged peripheral surface of the work is moving upwardly against the grinding wheel. In accordance with a feature of the present invention, means are provided to insure the rotation et the work in the proper direction for each of the alternative reversed positions of the headstock and footstock as represented in Figs. 1 and 2. For this purpose, a three phase headstock motor is employed, the direction et rotation of which is determined by the order in which the three phase lines are connected to the motor. The motor is driven from a main three phase power line in the base of the machine, and terminates in two directional outlets 54 and 56 located at opposite ends of the table and arranged to receive a plug 58 on a flexible electric cable 60 through which power is transmitted to the headstock motor 32. The outlets 54 and 56 are so arranged that the plugging of the plug 58 and electric cable 66 into the outlet 54 as shown in Fig. 1, will cause the headstock motor 44 to be rotated in one direction as designated by the arrow. whereas, plugging the cable 58 into the outlet 56 will cause the headstock motor 44 to rotate in the opposite direction in accordance with the illustration in Fig. 2.

The electrical driving connections for the machine are shown in greater detail in Fig. 4 of the drawings. Power is supplied by a three phase power line D, L and L The current is then transmitted through a secondary line T3l, T32 and T33 to each of the outlets 54 and 55. As clearly shown in Fig. 4, the outlets 54, 56 are each provided with one large socket and three small sockets which are arranged to engage with correspondingly placed prongs of the plug 58. It will also be evident from an inspection of the electrical diagram Fig. 4, that the phase limes T32 and T33 are reversed With respect to one another in the outlets 54, 56, so that the transfer of the plug 58 from one or the other of these outlets will act to reverse the direction of rotation of the headstock motor 44.

The footstock 34 with its swivel mounting 38 is adjustably secured to the table 40 y means of clamping screws 64 which extend downwardly at an angle through the swivel mounting 38, and are provided at their lower ends with enlarged heads engaging within the T-shaped 5101; 52 extending along the length of the table ways. The footstock is provided with a tapered dead center 66 which is fitted into a footstock spindle 68 adjustably supported within a housing 16 having a manually operable clamping screw H and associated clamping blocks 69. The construction and arrangement of the footstock is such that the center line of the center 66 and spindle 68 passes transversely through the axis ci. rotation et the footstock 34 on its swivel mounting 38, so that reversal of the position of the footstock on the table guideway will not alter the position of the line of centers of the work.

In accordance with the usual practice, the footstock spindle 68 is arranged to be shifted axially into and out of work engaging position by means of mechanism which is adapted for engaging the footstock center 66 against the work under a predetermined spring pressure before the clamp il is tightened to lock the footstock in position. Means is also provided for producing a fine adjustment of the footstock spindle 68 and center 66 axially with respect to its actuating mechanism.

As best shown in Fig. 6 of the drawings, the spindle 68 has screw-threaded into the rear end thereof an adjusting screw-threaded shaft 12 which ca-rries at its outer end a hand wheel 13. The shaft 12 is rotatably supported within a sleeve 74 which engages at one end against the sleeve hub of the hand wheel 13 and at its other end against a collar 15 on the shaft 12, In the present construction the sleeve 14 is slidably supported and is keyed to turn with a sleeve member 16 which is in turn externally supported for rotational movement within a split clamp bearing 18 in the footstock 34. As best shown in Figs. 7 and 8, the clamping screw 86 of this bearing is arranged to engage in an annular groove 82 extending half way around the circumierence of the sleeve member 76, thus locking the sleeve member 76 against axial movement while permitting a limited rotational movement of the sleeve member 76 whenever clamping pressure of the split clamp I8 is eased by backing oi the clamping screw 80. The sleeve member 16 serves as a housingfor the actuating mechanism above mentioned for advancing and retracting the footstock spindle 68. This actuating mechanism comprises a manually operable control lever 84 and a pair of compres sien spring-pressed plungers 65 which act on the control lever 84 in a direction to maintain the spindle 68 and center 66 yieldingly in an extreme forward position determined by the engagement of the shoulder on the sleeve 74 with the rear face of the sleeve member 16. The hand lever 84 is supported on a pivot pin 86 carried on two rearwardly extending lugs 88 on the sleeve member 16. An extension 90 of the lever 84 engages within a socket 92 inthe sleeve 14 to provide an operative connection between the lever and the footstock spindle. TWO arms 94 extending from the hub portion of the lever 84 engage against the spring-pressed plungers 85 which tend to swing the lever 84 in a counter-clockwise directien as shown in Fig. 8, to maintain the spindle in its forward position. In order to permit the locking of the footstock in a fully' retracted position against the pressure of the plungers 85, a radialiy extending detent 98 is provided in the sleeve member 15 which can be shifted inwardly into locking engagement with a recess me in the s1eeve 14 when the sleeve 14 and spindle Connected therewith have been moved to their fully retracted position.

In accordance With one feature of the invention, the footstock is particular1y constructed and arranged so that the hand lever 84 may be readi1y shifted from one side to the other of the headstock in order to place this element in the most accessible position for the operatr, dependng on whether the headstock is located in one or the other of its reverse positions at opposite ends of the table. With the construction above illustrated and described, the hand lever 84 may be readily shifted from one side to the other of the headstook by merely loosening the clamping screw 80, and thereafcer by turning the entire assemb1imaludng the lever 84, the supporting s1eeVe member 16 with the sleeve M through 180 to the alternative limiting position which is determined by the engagement of the clamping screw 80 With the opposite end of the locking groove 82. The screw 80 is then again tightened up to look the parts in their adjusted position.

Another feature of the present invention consists in the construction and arrangement of the footscoek to enable a footstock type diamond tool holder for grinding wheel truing to be located in a proper position of adjustment for each of the reverse operating positions of the footstook at opposite ends of the table. As best shown in Figs. and 6 of the drawings, the truing tool holder comprises a holder IM within which is supported a diamond tool lll6. The holder 134 is formed with a bearing surface [08 which engages the upvuper side of the dead center 66 and a semi-circular downward extension having a clamping screw Il!) which is tightened against the opposite side of the center 65. An upward extension of the holder l04 is journalled to receive a forwardIy extending positionixig pin 2 rigid1y located on the footstock. The pin H2 is secured in an upvvardly extending arm of a bracket H4 which is rigidly secured to the forward end of the spindle (58, and serves also to provide a dust guard for the spindle bearing. A set screw HG on the bracket H4 serves to secure the pin H2 in position in the bracket. A set screw Il! provided in the holder IB serves to secure the holder to the positioning pin H2. It will 'be noted that the positioning pin HZ is located at one side of a vertical plane passing through the axis of the foot stock spind1e 63 and the center 66. This offset is required to provide a clearance for the positioning pin H2 and the upper portion of the truing tool holder l4, supported thereby during the truing operation. 7

When the footsteck is shifted from the position of Figs. 1, 5 and 6 to its reverse position at the opposite end of the table, as shoWn in Fig, 2, it is required also to reverse the position of the truing tool holder M on the footstock to the position shown in Fig. 2. One feature of the invention consists in the provision of a truing tool holder s0 constructed and arranged as to permit it to be located on the center 66 in either of the reverse positions illustrated in Figs. 1 and 2, and.

in the provision of means cooperating therewith line position shown in Fig. 5 to the dot-and-dash position of Fig. 5, so that the truing tool may be supported, and may be given the proper set with relation to the grindng wheel in each of the reverse positions of the footst0ck as shown in Figs. 1 and 2. The truing tool holder and its adjnstable support are constructed and arranged to insure adequate c1earance of the supporting parts with relation to the grindimg wheel for each of the reverse positions illustrated. To this end the spindle 68 and associated bracket 1 I4 are arranged to be maintained in either of two alternative angu1ar positions which serve to locate the positioning pin H2 equa1 distances to one side or the other of the axis of the spind1e 68 and center 66. The angular position of the footst0ck spindIe 68 is deterznined by means of a pin I20 which is screw-fitted into the footst0ck housing, and engages in either of two slots l22, I24 in the external periphery of the spindle 68, as best shown in Figs. 8 and 9.

When the fobtstoak is moved from the position illustrated in Figs. 1 and 5 to 9 inclusive, to the reverse position of Fig. 2, the truing tool holder HJ4 is first removed, the clamp screw H6 being backed off to release the pin 2 and the clamping screw i Il! being similarly backed off to release the holder from the center 66. The screw pin l2ll is backed off to permit rotation of the footstock spindle 68 and the truing tool supporting bracket ll4 through a small angle to the left from the position of Fig. 5 until the aperture for the positioning pin l l2 reaches the dot-and-dash position for the pin H2 designated by the dot-and-dash lines of Fig. 5. The screw pin I20 is now screwed into engagement with the slot l24 (ses Fig. 9) thus lockng the parts in the alternative angular position. It is also necessary to reset the center 66 with relation to the spind1e 68 to bring the flattened portion thereof again into vertical position. In order to apply the truing tool holder l04 to the spind1e in its reverse position, it is now necessary only to loosen the set screw i I! and to shift the holder 104 to the opposite end of the pin, which is then fitted into the aperture in the bracket A. The grinding tool holder is then secured in position by the tightening of the clamping serews l I6 and I IE1,

It Will be understood that the invention is not limited to the specific embodiment shown,and that various devations may be made therefmm without departing from the spirit and scope of the appended claims.

The invention having been descrbed, what is claimed is:

1. In a grinding machine, the combination with a grindng wheel, of a Work supporting assembl comprising a work table having a guideway including a pair of positioning surfaces Iying in substantally vertical and horizontal planes re spectively, a headstoek and a footstock each having cooperating vertical and horizontal positioning surfaces and a swivel mounting, and means for securing said swivel mountings under pressure against both of said psitionng surfaces on the guideway, headst0ck and footstoek spind1es havmg their axes passing through the axes of said swivel mountings whereby said headstaek and footst0ck are freely interchangeable on said guideway t0 permit the headstock to be located a1ternative1y at either side of the grinding wheel on the table, and power means for driving the headst0ck including means for reversing the di-.

for shifi;ing the positionn'g pin H2 from the full rection of drive upon shiftine from one to the other of said alternative positions.

2. In a grinding machine, the combination with a grinding wheel, of a work support assembly comprising a work table having a guideway thereon including a pair of positioning surfaces lying in substantially vertical and horizontal planes respectively, a headstock and a footsteck each having cooperating vertical and horizontal positiomng surfaces and a swivel mounting, and means for securing said swivel mountings under pressure against both of said positioning surfaces on the guideway, headstock and footstock spindles having their axes passing through the axes cf said swivel mountings whereby said headstock and footstock are freely interchangeable on said guideway to permit the headstock to be located alternatively at either side of the grinding wheel on the table, power means for driving the headstock, and means connectible in shiiting the position of the headstock from one side to the other of the grinding wheel to reverse the direction of the headstock drive.

3. In a grinding machine, the combination with a grinding wheel, of a work support assembly comprising a work table having a guideway thereon including a pair of positioning surfaces lying in substantially vertical and horizontal planes respectively, a headstock and a footstock each having cooperating vertical and horizontal positioning surfaces and a swivel mounting, and means for securing each of said swivel mountings under pressure against both of said positioning surfaces on the guideway, headstock and footstock spindles having their axes passing through the axes of said swivel mountings whereby the headstock and footstock are freely interchangeable on the guideway to permit the headstock to be located alternatively at either side of the grinding wheel on the table, an electric motor on the headstock for driving the headstock, and electrical power connections for the headstock motor including a directional electrical outlet adjacent each end of the table, and a plug connection for electrically connecting the motor through one of said outlets in each of said interchangeable positions, said electrical outlets and plug connection cooperating therewith being constructed and arranged to cause the motor to be driven through one outlet in one direction and through the other outlet in the opposite direction.

4. In a grinding machine, the combination with a grinding wheel, of a work supporting assembly comprising a work table having a guideway thereon, a headstock and a footstock interchangeably supported on said guideway to locate the headstock alternativcly to opposite sides of the grinding wheel, headstock and footstock spindles, connections including a manual control element for eiecting axial movement of the footstcck spindle in the footstock, and means in said connections shiftable to locate the manual control element in alternative positions at opposite sides of the footstock.

5. In a footstock, the combination with a swivel mounting, a spindle housing swivelling thereon, and a spindle axially movable in the housing, of means for moving the spindle axially including a manually operable spindle shifting lever, a support for said lever shiftable angularly about the spindle, and means for securing the support in either of two alternative angular positions in which the manual lever is accessible to the operator from one side or the other of the footstock.

6. In a footstock, the combinati on with a spindle housing and a spindle axially movable therein, of means for moving the spindle axially including a manually operable spindle shifting lever, a sleeve support for said lever shiftable angularly about the spindle, a bearing for the sleeve including means to prevent axial movement of the sleeve support relative to the footstock. and means for securing the sleeve support in either of two alternative positions in which the manual lever is located at one or the other side of the footstock.

7. In a grinding machine, the combination with a grinding wheel, of a Work supporting assembly comprising a work table having a guideway thereon, a headstock and a footstock interchangeably supported on said guideway to permit location of the headstock to opposite sides of the grinding wheel, a footstock spindle, a grinding wheel truing tool holder, off-set supporting means for the tool holder on the footstock spindle arranged for supporting the tool holder in alternative positions facing toward one side or the other of the footstock, and means for securing the spindle alternatively in either of two predetermined angular positions toprovide identical positions of support for the tool holder facing opposite sides of the footstock.

8. In a grinding machine, the combination with a grinding wheel spindle, of a work supporting assembly including a work table, a headstock and a footstock interchangeably supported on the table, a footstock spindle, a footstock center, a support on the footstock spindle off-set to one side of a vertical plane passing through the axis thereof and including a positioning pin parallel with the spindle axis, a grinding wheel truing tool holder arranged to be supported on the footstock c-enter and positioning pin in alternative positions facing toward one side or the other of the footstock, and means for positioning the spindle in either of two alternativ predetermined angular positions in which the positioning pin is off-set on opposite sides of said vertical plane whereby said tool is given the proper set in each of said reverse positions.

9. In a grinding machine, a base, a grinding wheel with supporting means mounted on the base, work supporting and rotating means mounted on the base comprising a table having a guideway thereon and a headstock and a footstock interchangeably supported on said guideway and locatable alternatively on opposite sides of the grinding wheel, headstock and footstock spindles, an electric motor for driving the headstock, and connections for operating the headstock and footstock when positioned on either side of the grinding wheel comprising a directional electrical outlet in the base adjacent each end of the table t0 cause the h6adstock to be driven in reverse directions when the headstock is Shifted from one side to the other of the grinding wheel and manual control means for the footstock spindle including a lever and an element shiftable te locate the lever in two alternative positions in which it is accessible to the operator from on side or the other of the footstock.

10. In a grinding machine, the combination with a grinding wheel, of a work supporting assembly comprising a work table having a guideway including a pair of positioning surfaces lying in substantially vertical and horizontal planes respectively, a headstock and a footstcck each having a swivel mounting, and means for securin said swivel mountings under pressure against both of said positioning surfaces on the guideway, headstock and footstock spindles having their axes passing through the axes of said swivel mountings whereby said headstock and footstock are freely interchangeable on said guideway to permit the headstock to be located alternatively at either side of the grinding wheel on the table, power means for driving the headstock including means for reversing the direction of drive upon shifting from one to the other of said alternative positions, connections including a manual control element for efiecting axial movement -of the footstock spindle and the footstock, and means in said connections shiftable to locate the manual control element in alternative positions at opposite sides of the footstock.

11. In a grinding machine, the combination with a grinding wheel, of a work supporting assembly comprising a work table having a guideway including a pair of positioning surfaces lying in substantially vertical and horizontal planes respectively, a headstock and a footstock each having a swivel mounting, means for securing said swivel mountings under pressure against both of said positioning surfaces on the guideway, headstock and footstock spindles having their axes passing through the axes of said swivel mountings whereby said headstock and footstock are freely interchangeable on said guideway to permit the headstock to be located alternatively at MAXWELL I. MATHEWSON. 

